Create a command for building + running unit tests

[asteurer]

While possible to build and run unit tests, it is tedious and error-prone. It would be good to have a command like componentize-go test run --build to make it simpler. An example of the guts of this can be found in opentelemetry-wasi:

GOOS=wasip1 GOARCH=wasm go test -ldflags=-checklinkname=0 -c -o test.wasm ./example \
        && wasmtime run test.wasm

[asteurer]

I'm realizing that some folks might want unit tests that make use of wasip2+ features, so we need to make sure this is included.

Somewhat related: If we end up deciding to include wasip1 test compilation, maybe we need to also include wasip1 application compilation as part of componentize-go?